Cryogenic thermophysical studies for clinical medicine

Cryogenic technology has been widely used in clinical medicine and in pharmaceutics, so thermophysical studies are extremely important to solve problems during freezing and thawing. This paper reports some recent research in clinical medicine, including cryo-injury, cryosurgery, and cryopreservation of some important cells and tissues. Microscopic images of the freezing process with a cryomicroscope system show that the dendritic ice growth is affected by the solution concentration, the cooling rate, and the number of embryos. An enthalpy method is used for the freeze-thaw analysis of the cryosurgery with a program developed to predict the temperature profile and the interface motion, which compares well with experimental results. A very rapid cooling technique is developed by quenching the samples into subcooled liquid nitrogen for vitrification of cells and tissues. An analytical method developed to prevent the fracture of arteries during freezing has been verified by the electronic microscopic investigation.